JPH06183330A - Electric assist type brake device - Google Patents

Abstract

(57) [Abstract] [Purpose] For example, even in an electric vehicle that does not have an engine, it is possible to easily generate a braking assist force to realize a light brake operation, and to perform various operations without changing the basic mechanism. To be applicable to. [Structure] An electric motor 11 capable of applying a direct power to a piston of a master cylinder 2 is provided, and a pedaling force sensor 8 for detecting a pedaling force of a brake pedal 3 is provided, and a controller 10 operates according to a detection result of the pedaling force sensor 8. The electric motor 11 is driven. The master cylinder 2 and the brake pedal 3 are mechanically separated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake system which obtains a braking force by a hydraulic pressure generated by a master cylinder, and in particular, an assist force can be obtained without utilizing a suction negative pressure of an engine. , Functions such as anti-lock braking system can be easily introduced without requiring significant changes or additions to the mechanism, and further, the position where the brake is operated and the position where the brake is operated are often separated. It is designed so that even large vehicles are not subject to significant restrictions.

[0002]

2. Description of the Related Art A conventional hydraulic brake system has been developed for a normal vehicle having an engine, and the assist force of the brake is mainly generated by utilizing the suction negative pressure of the engine. It was Further, in such a conventional configuration for generating an assisting force, since it is an independent device by itself, it is necessary to add a device of another system corresponding thereto in order to introduce, for example, an antilock brake system or the like. .

[0003]

Certainly, a normal vehicle having an engine can easily obtain the assisting force of the brake by utilizing the suction negative pressure of the engine. However, in an electric vehicle having no engine, It could not be easily applied. That is, in order to apply the configuration for obtaining the assisting force of the brake by the negative pressure to the electric vehicle, for example, the vacuum pump must be driven by the electric motor to accumulate the negative pressure, which leads to an increase in the size of the device. I will end up.

Further, as described above, in the conventional structure for generating the assisting force, in order to add another function,
There is also a problem that a device of a different system must be added according to it, and the device becomes complicated and expensive. further,
The conventional hydraulic brake device has a configuration in which the hydraulic pressure generated by the master cylinder directly connected to the brake pedal is distributed to each braking wheel, so that its application is restricted by the piping or the like for transmitting the hydraulic pressure. There are also points.

The present invention has been made by paying attention to the unsolved problems of the prior art as described above, and the assisting force of the brake can be easily obtained even in a vehicle having no engine. Another object of the present invention is to provide a hydraulic brake device that can easily introduce other functions and can be easily applied to a wide range of applications.

[0006]

In order to achieve the above object, the present invention provides a master cylinder that generates a hydraulic fluid pressure for a brake, an electric motor that generates a braking assist force, and a rotational force of this electric motor. Rotational force converting means for converting into direct power of the piston of the master cylinder, operation status detecting means for detecting a brake operation status of the brake operating section, and driving the electric motor according to a detection result of the operation status detecting means. And a controller, and the master cylinder is mechanically separated from the brake operating unit.

[0007]

When the operation status detecting means detects the operation status of the brake operation section (for example, the brake pedal) (for example, the depression force of the brake pedal), the controller drives the electric motor according to the detected operation status. For,
Rotational force is generated in the electric motor according to the operating condition of the brake operating unit.

Then, since the rotational force is converted into the direct power of the piston of the master cylinder by the rotational force converting means, the master cylinder generates hydraulic fluid pressure for the brake, and the braking force is generated there. Further, since the master cylinder is mechanically separated from the brake operating unit, when applied to an application such as operating a brake in a towing vehicle to apply a braking force to the wheels of the towed vehicle, When connecting or disconnecting with the towed vehicle, the procedure for the brake system is completed by connecting or disconnecting the electrical connector.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of the present invention, FIG. 1 is a view showing the entire electric assist type brake device 1, and FIG. 2 is a vertical sectional view showing the structure of a master cylinder 2.

First, the structure will be described. The master cylinder 2
Is a brake pad that tightens the brake disc 4 by pressing the pedal force of the brake pedal 3 as a brake operating unit,
This is a device for converting the hydraulic pressure of the brake unit 5 including a wheel cylinder and the like, and hydraulic pressure is transmitted between the master cylinder 2 and the brake unit 5 through a pipe 6.

Further, one end of a shaft 7 which is axially movable back and forth is connected to the middle of an arm portion which supports the brake pedal 3 on the vehicle body, and the other end of the shaft 7 is swingably connected to the vehicle body. . Here, there is no mechanical means for directly transmitting the pedaling force of the brake pedal 3 to the master cylinder 2, such as a link or hydraulic piping. A pedaling force sensor 8 as an operating condition detecting means for detecting the pedaling force as the operating condition of the brake pedal 3 is provided in the middle of the shaft 7. The pedaling force sensor 8 detects the pedaling force of the brake pedal 3 based on, for example, an axial stress generated on the shaft 7.

The pedaling force of the brake pedal 3 detected by the pedaling force sensor 8 is supplied to a controller 10 including a microcomputer, an interface circuit, a drive circuit and the like. On the other hand, an electric motor 11 is arranged in parallel with the master cylinder 2 and
Is controlled by the controller 10 to generate a braking assist force as described later.

The master cylinder 2 is, as shown in FIG.
The primary cup 1 has a piston 12 that moves forward and backward in the left-right direction in the drawing, and is formed at the tip of the piston 12.
A hydraulic chamber 2b defined by 2a and the housing 2a communicates with the brake unit 5 via a pipe 6. A return spring 13 for returning the piston 12 to its original position is arranged in the hydraulic chamber 2b.

A secondary cup 12b is formed on the other end side of the piston 12, and the secondary cup 12b is formed.
On the right side in the figure of b, a hollow cylindrical portion 12 whose right end side is open
c is integrally formed. Further, in the housing 2a, a ball screw screw shaft 15 which is rotatable by bearings 16a and 16b but prevented from moving in the axial direction is disposed, and the tip of the screw shaft 15 is It has entered into the cylindrical portion 12c.

A ball screw nut 17 screwed onto the screw shaft 15 is coaxially fixed to the end of the cylindrical portion 12c. A convex portion 17a protruding in the radial direction is formed on the outer peripheral surface of the nut 17, and the convex portion 17a is formed in the housing 2a and is fitted in the axially long guide groove 2c. Only rotation is prevented without restricting the movement of the nut 17 in the axial direction.

A large gear 18A is externally fitted to the screw shaft 15, and the small gear 18B and the electric motor 11 are rotatably supported in the housing 2a.
The rotational force of the electric motor 11 is transmitted through the small gear 18C fixed to the output shaft 11a.
A reservoir tank 19 is provided integrally with the housing 2a immediately above the portion in which the piston 12 is present, and brake oil is sealed in the reservoir tank 19.

The reservoir tank 19 and the hydraulic chamber 2b can communicate with each other via a relief port 20. The space defined by the primary cup 12a and the secondary cup 12b also communicates with the reservoir tank 19 via the passage 21. Next, the operation of this embodiment will be described.

When the operator depresses the brake pedal 3, the shaft 7 flexes in the axial direction according to the pedaling force, so that the pedaling force of the brake pedal 3 is detected by the pedaling force sensor 8, and the controller 10 is electrically operated according to the pedaling force. Since the motor 11 is rotationally driven, a rotational force is generated in the electric motor 11,
The rotational force is the small gears 18C, 18B and the large gear 18A.
It is transmitted to the screw shaft 15 while being decelerated via.

The screw shaft 15 is rotatable but cannot move in the axial direction, and the nut 17 can move in the axial direction but its rotation is restricted. When is rotated, the nut 17 screwed onto this moves back and forth in the axial direction. That is, the rotational force of the electric motor 11 is converted into the direct power of the piston 12 via the small gears 18C and 18B, the large gear 18A, the screw shaft 15 and the nut 17. Here, in the present embodiment, the guide groove 2
c, screw shaft 15, bearings 16a, 16b, nut 1
7, convex portion 17a, large gear 18A and small gear 18B, 18
The rotational force converting means is constituted by C.

Then, the piston 12 integrated with the nut 17
Also moves to the left, and when the primary cup 12a moves to the left in FIG. 2 from the relief port 20, the hydraulic chamber 2b is separated from the reservoir tank 19 and becomes a sealed state,
After that, the hydraulic pressure corresponding to the pushing force of the piston 12 is applied to the hydraulic chamber 2.
occurs within b. Since the hydraulic pressure in the hydraulic chamber 2b is transmitted to the brake unit 5 through the pipe 6, the wheel cylinder operates and the brake pad is pressed against the brake disc 4, and a braking force is generated there.

As described above, as a result, the braking force is generated by the driver stepping on the brake pedal 3, but the pedaling force of the brake pedal 3 is converted into an electric signal by the pedaling force sensor 8, and the signal is converted. According to the controller 10
Drives the electric motor 11 and converts the rotational force of the electric motor 11 into the direct power of the piston 12 to generate a braking force. Therefore, the force generated by the electric motor 11 is larger than the pedaling force of the brake pedal 3. Control contents of the controller 10 and the large gear 18A and the small gear 18
If the tooth ratio of B and 18C is determined, the braking assist force is generated by the electric motor 11, the burden on the operator is reduced, and a sufficient braking force can be obtained by a light brake operation.

When the pedal force of the brake pedal 3 by the operator is released, the piston 12 is pushed back by the hydraulic pressure in the hydraulic chamber 2b and the urging force of the return spring 13, and the primary cup 12a is pushed more than the relief port 20. When the hydraulic chamber 2b moves to the right in FIG. 2, the hydraulic chamber 2b is opened and the braking force is lost. As described above, according to the configuration of this embodiment, since the electric motor 11 can apply the braking assist force to the hydraulic brake device, it can be easily applied to an electric vehicle without an engine, for example. You can

Then, for example, the controller 10 is caused to execute a control for detecting the rotation of the braking wheel, and determining the locked state of the wheel during braking according to the detection result of the sensor and temporarily releasing the brake. Thus, a so-called anti-lock braking system can be introduced without modifying other structures. That is, with the configuration of the present embodiment, various sensors can be provided by simply providing necessary sensors and changing the program stored in the controller 10 so that the controller 10 appropriately executes control according to the detection result. The function of can be added.

For example, a master cylinder 2 is provided for each of the two wheels driven by one final reduction gear, and the number of rotations of each wheel is detected to determine whether one wheel is in a slip state. , The controller 1 so that the brake is applied only to one wheel in the slip state.
By changing the program within 0, it is possible to configure a so-called non-slip differential device that can generate a large torque on the other wheel that is not in the slip state.

Further, if the controller 10 is provided with a function of operating the brakes by an external control signal, it can be easily applied to a system which autonomously travels while maintaining a uniform distance from the preceding vehicle. In this case, a device for issuing a control signal from the outside and a device for receiving the signal in the vehicle constitute a brake operation unit instead of the brake pedal 3.

In this embodiment, the brake pedal 3 that is actually operated by the operator and the master cylinder 2 that generates the hydraulic fluid pressure for the brake are mechanically separated. For example, it can be suitably used for a brake device of a towed vehicle of a vehicle such as a trailer that constantly connects or disconnects the towed vehicle and the towed vehicle. That is, if the controller 10 side is mounted on the towing vehicle side and the master cylinder 2 side is mounted on the towed vehicle side, the controller 10 and the electric motor are connected when connecting and disconnecting the towing vehicle and the towed vehicle. This is because the treatment of the brake system is completed by connecting or disconnecting the cable connecting between 11 with the electrical connector.

Incidentally, in the case of the conventional hydraulic brake device, since the brake pedal 3 and the master cylinder 2 need to be mechanically connected, the restriction of the pipe 6 is imposed, which is suitable for a vehicle such as a trailer. It cannot be used for. When the electrically assisted brake device 1 of the present embodiment is applied to a vehicle such as a trailer, the type of the brake device on the towing vehicle side is not particularly limited, and has the same configuration as that of the present embodiment. It may be a conventional structure. However, when the towing vehicle-side brake device has the conventional structure, it is necessary to provide the pedal force sensor 8 in the towing vehicle-side brake device.

As described above, with the structure of this embodiment, not only can it be suitably used as a brake device for an electric vehicle that does not have an engine, but it can also be easily used for various applications without changing the basic mechanism. It becomes possible to use. Although only one braking wheel is shown in FIG. 1, the present invention may be applied to a two-wheeled vehicle, a four-wheeled vehicle, or a vehicle having more wheels.

Further, in the above-mentioned embodiment, the case where the depression type brake pedal 3 is used as the brake operating portion is explained, but the control contents of the controller 10 and the large gear 1 are described.
8A and the small gears 18B and 18C can be set to a lever-like one for manually operating the brake operating portion by appropriately setting the gear ratio.

[0030]

As described above, according to the present invention,
The electric motor is driven according to the operation status of the brake operation unit to generate a braking assist force, and the brake operation unit and the master cylinder are mechanically separated from each other. Even if it is, it is possible to easily generate a braking assist force and realize a light brake operation, and it is possible to add various functions and apply it to many applications without changing the basic mechanism. The effect of being able to be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an entire system according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a master cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric assist type brake device 2 Master cylinder 3 Brake pedal (brake operation part) 5 Brake unit 8 Treading force sensor (operation status detection means) 10 Controller 11 Electric motor 12 Piston 15 Screw shaft 16a, 16b Bearing 17 Nut 18A Large gear 18B, 18C small gear 20 relief port

Claims (1)

[Claims] 1. A master cylinder for generating a hydraulic fluid pressure for a brake, an electric motor for generating a braking assist force, and a rotational force conversion means for converting the rotational force of the electric motor into a direct power of a piston of the master cylinder. And a controller for driving the electric motor according to a detection result of the operation status detecting means, and a controller for driving the master cylinder from the brake operating section. The electrically assisted braking device is characterized by being separated.